Additional Study Information: The goal of this study is to better understand the genetic causes of weight gain. Your participation will help us understand how why some people gain more weight and why others do not.We will ask you questions about your weight and your height to determine if you are eligible. If you are eligible, we will invite you to participate. To participate, we will ask you questions about your medical history and eating habits and ask you to provide a blood or saliva sample for genetic testing. We will test the DNA from your blood or saliva sample to try to identify if you have a genetic cause for your obesity.